The proposed 3-year competing continuation application is designed to extend work conducted previously which assessed the effectiveness of a promising school-based drug abuse prevention approach. During the planned follow-up, data would be collected from a cohort of individuals (N=5,954) who began participation in this longitudinal study in the fall of 1985 when they were 7th graders. Schools (N=56) were randomly assigned to two treatment and one control condition. Individuals in the treatment group received a 15-session prevention program in grade 7, a 10 session booster intervention in grade 8, and a 5 session booster intervention in grade 9. All participants were pretested and posttested by questionnaire in grade 7 and assessed annually in grades 8, 9, and 10 as well as at the end of grade 12. Included were items concerning self-reported tobacco, alcohol, and marijuana use as well as items/scales assessing drug-related knowledge, attitudes, norms, resistance skills; personal and social skills; and an array of psychosocial variables (e.g., self-esteem, self- efficacy). In addition to collecting data on these variables, new questionnaire items will be added to assess illicit drug use and psychosocial functioning. During the continuation period, data would be collected to determine the long-term effectiveness of the preventive intervention on both licit and illicit drug use, hypothesized mediating variables, and new outcomes regarding psychosocial functioning. At this point, about 90% of the individuals who previously participated in this study have been located using New York State's DMV database. The current research team will be strengthened on this additional work by the addition of three experienced longitudinal investigators (Drs., Michael Newcomb, Robert Pandina, and Michael Windle) and an outstanding survey research firm (Response Analysis) who have achieved impressive results on similar past studies. The work proposed offers the potential of significantly increasing our understanding of the durability of a promising prevention approach, its mediating mechanisms, and provide further information concerning the etiology of drug use over a critical 10 year period ranging from early adolescence to early adulthood. This work also has significance because of the association between injection drug abuse and AIDS and the potential of identifying an intervention capable of also reducing risk for HIV infection.